中文摘要：

对Buck恒流电源的纹波电流与电压进行了分析,导出了它们的数学式。用MATLAB计算并讨论了恒流源的输入电压、负载电压对输出纹波的影响,给出了电感和滤波电容的优化设计方法。设计了一款高性价比、可对探测器制冷控温的携式x荧光分析仪恒流电源。实验表明,输出纹波电压随输入电压的减少而减少,工作效率大于84%,纹波电压小于10mV,控温精度优于±1.5℃,测量结果与理论相符。

英文摘要：

The ripple current and voltage of a buck constant current power supply are analyzed, and the equa- tions of the ripple current and voltage are derived. According to the equations, the calculations are performed by MATLAB, and the effects of the input and load voltages on the output ripples are discussed. Then, the opti- mal design methods of the inductor and filter capacitor are presented. A cost - effective buck constant current power supply for cooling and controlling the temperature of the Sin - PIN detector in a portable x - ray fluorome- ter is designed. The experiment shows that the designed power supply ’s output ripple voltage decreases with the smaller input voltage; its operating efficiency is greater than 84% ; output ripple voltage less than 10mV; and temperature control accuracy superior to ± 1.5℃. These measured results are in agreement with the derived equations.